PRE-PAS: Christian Dior opened up its 57th Street boutique on Tuesday night for a cocktail reception in honor of the New York City Ballet’s upcoming spring gala on May 10, which the fashion house will co-sponsor, and to offer a look at its latest jewelry collection, My Dior. A slew of socials and the occasional dancer turned out for the very civil cocktail hour, including event hosts Donya Bommer, Olivia Chantecaille, Michele Herbert, Pamela Joyner, Alexandra Kerry and Carol Mack. Gala honorary chairman Natalie Portman was not in attendance, but her husband, the choreographer and former New York City Ballet principal Benjamin Millepied, seemed happy enough to pinch hit. Millepied collaborated with composer Nico Muhly on a new ballet that will be performed at the gala (with costumes by Kate and Laura Mulleavy of Rodarte) and was a guest of honor at the boutique. He declined to offer any details of the upcoming performance but did let on that his recent marriage was having an effect on his creative process. “Having a family, having a child is such a rush of emotion, such an overwhelming rush of good emotions that it really throws you up in the air,” he said.